FIELD OF THE INVENTION
The invention relates to a method of performing operating steps in an adjustment of a printing press, preferably in the conversion of a sheet-fed printing machine press for recto/verso or first form and perfector printing wherein adjusting members preloaded in one direction of motion are displaceable in chronologically, at least partly successive or sequential operating steps in a direction opposite to the one direction by means of adjusting cylinders upon which a pressure medium is actionable, and to a device for performing the foregoing method.
Adjustable printing presses, especially printing presses which are convertible between one-sided and two-sided printing, have become known heretofore in many different versions, for example, from U.S. Pat. Nos. 5,076,164; 5,085,143; 5,033,379; 5,105,737; 5,031,531 and 4,014,261. The last-mentioned reference describes a printing press for printing sheets in the one-sided and two-sided printing modes, wherein a sheet arriving from a printing unit is gripped at the leading edge thereof by the gripper system of a transfer drum and transferred by the leading edge to the gripper system of a storage drum, which delivers the sheet to a further drum before the sheet arrives in the next printing unit. In two-sided printing, the latter drum serves as a sheet inverting drum. The sheet is then gripped at the trailing edge thereof by a gripper system of the inverting drum, which performs a 180.degree. swivelling motion, so that the turned-over sheet then enters the next printing unit with the trailing edge thereof in leading position and printing is then performed on what was previously the reverse side thereof.
To convert the printing press from one-sided, i.e., first form or recto, printing to two-sided, i.e., first form and perfector or recto/verso, printing, or to bring the sheet inverting device into engagement and to disengage it again, it is necessary, in a first step, for the transport drums which are driven, for example, by a common gear train, to be brought into a defined conversion position (zero position) wherein a zero-position pulse or signal is transmitted, for example, by an incremental angle encoder, such as is described in published British Patent Document GB 2 225 556 A.
Only after the foregoing first step has been performed, can the phase relationship of the printing units to one another be adjusted in a further step, wherein a nonrotatable first element in the printing press drive system is held fast, and an adjustable second element of the drive system is rotated a defined angular amount relative to the first element. For holding the nonrotatable element fast, conventional means such as catch members, clamping jaws and the like may be used. The adjustment of the rotatable element is effected either by the main drive of the printing press or by an additional adjusting drive.
In yet another step, the opening times for the grippers of the drums which receive the sheet and which transfer the sheet are adjusted. The control members for setting the instants of the gripper opening times are adjustable in infinitely graduated fashion and are connected to the respective transport drum by clamping, so that this clamping must first be released before the control members for the gripper opening times of both the inverting drum and the storage drum can be displaced by means of separate drive elements. In another step, a device holding the trailing edge of the sheet of a transport drum serving as a storage drum can be adjusted to the end of the respective sheet following thereafter, in accordance with the sheet size or format. Once again, a clamped connection must first be released before it is possible to adjust the angular position of this device relative to the grippers which hold the leading edge of the sheet.
Finally, all the connection which have been released must be remade or connected again after the conversion has been effected. The published German Patent Document DE 31 36 349 A1 and German Utility Model DE-GM 83 19 431 disclose hydraulic adjusting cylinders for loosening and tightening the clamping devices of the transport drum control elements which are adjustable for conversion of the printing press, but rotary ducts for supplying the hydraulic fluid to the working cylinders are necessary, because the latter are disposed on drums which rotate. For every switching or tightening operation, one or even more pressure lines are required, so that expensive multiple rotary ducts are necessary.